School of Physical and Occupational Therapy, McGill University, Montreal, Quebec, Canada; Centre for Interdisciplinary Research in Rehabilitation, Montreal, Quebec, Canada.
Gait Posture. 2014;39(1):378-85. doi: 10.1016/j.gaitpost.2013.08.011. Epub 2013 Aug 18.
Many falls in older adults occur during walking following trips. Following a trip, older adults take longer than younger adults to recover steady-state walking. Although faster gait speed may improve interlimb coordination, it may also increase fall risk in older adults. We hypothesized that older adults would take longer than younger adults to recover from an unexpected perturbation during gait especially when walking faster. Twelve younger (26.3 ± 4.4 years) and 12 older adults (68.5 ± 3.4 years) walked at comfortable, faster and slower speeds when movement of the dominant leg was unexpectedly arrested for 250 ms at 20% swing length. Gait stability was evaluated using the short- and longer-term response to perturbation. In both groups, walking faster diminished the occurrence of elevation and increased that of leg lowering. Older adults took longer than younger adults to recover steady-state walking at all speeds (3.36 ± 0.11 vs. 2.89 ± 0.08 strides) but longer-term recovery of gait stability was not related to gait speed. Arm-leg and inter-arm coordination improved with increasing gait speed in both groups, but older adults had weaker inter-leg coupling following perturbation at all speeds. Although both younger and older adults used speed appropriate responses immediately following perturbation, longer duration of recovery of steady-state walking in older adults may increase fall risk in uncontrolled situations, regardless of gait speed. Recovery from perturbation when walking faster was associated with better interlimb coordination, but not with better gait stability. This indicates that interlimb coordination and gait stability may be distinct features of locomotion.
许多老年人在行走时会因绊倒而摔倒。在绊倒后，老年人需要比年轻人更长的时间才能恢复到稳定的行走状态。虽然更快的步速可能会改善肢体间的协调性，但也可能会增加老年人摔倒的风险。我们假设老年人在行走中从意外的扰动中恢复的时间会比年轻人长，尤其是在走得更快的情况下。12 名年轻（26.3±4.4 岁）和 12 名老年（68.5±3.4 岁）被试以舒适、快和慢三种速度行走，此时主导腿在 20%摆动长度处突然停止摆动 250ms。采用短期和长期两种响应来评估步态稳定性。在两组中，走得越快，抬腿的发生次数就越少，而降低腿的次数就越多。在所有速度下，老年人恢复稳定行走的时间都比年轻人长（3.36±0.11 步对 2.89±0.08 步），但步态稳定性的长期恢复与步速无关。在两组中，手臂-腿部和手臂间的协调性随着步速的增加而提高，但在所有速度下，老年人在受到扰动后的肢体间耦合较弱。尽管年轻和老年人在受到扰动后立即使用了适合的速度响应，但老年人恢复稳定行走的时间较长，这可能会增加在不受控制的情况下摔倒的风险，而与步速无关。当走得更快时，从扰动中恢复与更好的肢体间协调性相关，而与更好的步态稳定性无关。这表明肢体间协调性和步态稳定性可能是两种不同的运动特征。
